The long term goal of this campaign is, as the title says, “To Build a City.” Each great city began with a few people finding a nice spot to settle down. This settlement grows and grows, until one day it is a thriving metropolis, a tool used by more powerful factions and nations, or a crumbling ruin overrun by creatures of all sorts.

The long term goal of this campaign is, as the title says, “To Build a City.” Each great city began with a few people finding a nice spot to settle down. This settlement grows and grows, until one day it is a thriving metropolis. This campaign is designed to let the party be that first group, to strike out and create a brand new city. It probably should not be the party’s intention to found a new city when they set out. The city evolves beneath them hopefully almost without them noticing until they look back and say “wait a minute, we are building a city!” It is probably a very good idea to have the book Cityscape at hand, especially for the second and third acts. Another good one is the 3e Stronghold Builder's Guide. If there is a similar book for 3.5e, I haven't found it. But this should do fine. I will try to include relevant information and cost of buildings that will be likely built. This will take some time to prepare for, as right now it is mainly bare bones. It is also planned for a long campaign.

At the beginning of this adventure, it is preferable that the characters be level 5 or above, but at most level 10 if you wish to make a shorter campaign, or only have this adventure be only part of the campaign. If the latter is the case, the DM should keep in mind that once this adventure is done, the party will be pretty much locked to the location, so long distance adventuring after it could prove difficult for the story. I am designing this for a party of level 5, to take them to level 20. A shorter campaign can always trim parts down.

This can be played with most compositions of parties; however, in the later parts of the campaign, rogues and other sneaky, skill based characters may have a harder time putting their specific talents to use. So while a rogue might be useful early on, he may want to think about taking levels in something more suited to running a city, or start a spie’s guild to help out in the politics. Another useful thing to keep in mind is that the campaign will probably run smoother if there is a specific member of the party who is or can develop into a leader, a character for whom it would be logical to become the principal leader of the city. This is a campaign where such a character might actually use the feat Leadership. However, the city being ruled by a governing council, a.k.a. the entire party, is also an option. There are many ways it can play out. Perhaps nobody in the party wants to be the ruler at all, so they set up an NPC as a ruler and are just his advisors (as in the people who actually make decisions, but who can still use Cha as their dump stat). But these considerations only have much weight towards the final stages, so any starting party will have plenty of time to evolve into something that fits the bill.

In the first act, the party must acquire of a spot of land, the sight of their future city. Once this is completed, they will then proceed to scout and make safe the surrounding area. An initial fortification will have to be set up, or existing fortifications repaired. Initial growth may be difficult, and can be expedited by having the players start near a small town or village over which they can gain sway. The development process will probably need some help from the DM, as a big part will have to be people moving in. But the development of the city itself is not a big part in this first act. It is mainly exploring the new territory and adding a few bits onto the town and fortifications. The main influx of people will most likely be workers, skilled and unskilled, to help with that.

The rough design of the initial adventure must result in the party taking possession of a plot of land that would be a good building site for a city. A decent adventure to let this happen can be found in the Wizards of the Coast adventure “Base of Operations” by Ed Stark found here http://www.wizards.com/default.asp?x=dnd/oa/20001001a.
The easiest (and extremely uninteresting) way would be to have them magically acquire a keep through something like a deck of many things.

A rough outline for a new adventure to fit the description is as follows:
The hook is that the party hears a rumor about treasure that can be found in remote woods (and we all know d&d rumors turn out to be true). This provides a good reason for the party to go out there and to stay once they are there while they look for the treasure. They come across a small farming community near a long abandoned keep. If the DM wishes to use the entirety of this campaign, the important things are that the community is next to mountains, a forest, and a river. The river is coming out of the mountains, and is mostly not navigable by larger vessels above the location of the town. At a point near the town, the river forks and then reconnects, forming a large island upon which the abandoned keep rests. The Island is much bigger than the keep currently is, allowing lots of room to expand and create a flourishing inner city.

When the party arrives at the village, it is being preyed upon by a group of bandits who have, surprise surprise, taken up residence in the now not-so-abandoned keep. The villagers are desperate for someone to help stop the bandits from forcing food and goods from them, and are willing to offer loyalty to anyone capable of ridding them of this burden, as well as help locating the aforementioned treasure. If the players accept the challenge, they will then confront the bandits next time they attempt to lighten the village of supplies. The group of bandits as a whole is fairly large, but the first encounter just takes place against a smaller group of them come to collect.
Once this initial group is repelled, and perhaps a few more smaller encounters with groups of bandits in the surrounding woods, the bandits decide to attack with force. It is a bitter battle, made a bit easier for the party as several townsfolk are willing to take part in the defense of their homes. But be careful not to endanger too many villagers, as the town may be crippled if many die.
Once the dust settles, the remaining bandits, if any, flee back to the keep. Then it becomes time for the party to make a counter strike. An assault on the keep could be challenging, but keep in mind that this keep is in a general state of disrepair, making it easier to gain entrance. The party then must clear out the remaining bandits, and eventually defeat the leader of the bandits. Once that is done, it is time to celebrate. The party is now in possession of a keep, and have the loyalty of a town along with it. If anyone asks, the name of the keep is "Silver Rock Castle," named after the way the rocks that form the southern tip of the island shine in the moonlight.

Notes: Obviously the biggest danger in this section is that the party refuses to help the villagers or decide not to stay in their new keep at the end. If the party cannot be convinced to stay, then this campaign idea will probably be a waste of effort. Oops. Players do stuff like that. If the players join the bandits, loot the town, and/or kill the townsfolk, then you are dealing with an evil party, and that is not what this is designed for.

So now the party has a keep. What to do with it? Fix it up. Make it bigger. Build a bathhouse. Build some docks. BUILD A PUB!!! Of course, to do all this, you need money. The first thing to do would encourage the players to try to set up trade with other places down the river. This should provide a steady income to allow for construction without making the PC too rich. Some nice things to have would be a few rowboats (50gp) to ferry things to your keep as well as possibly a keelboat (3000gp) for sending goods downriver. If you decide that the keep will not be near a river, then some wagons (35gp + cost of 2 horses) would be nice. Try to encourage the players to build up and settle in. *DM glancing through the source book* "Oh, look how much money you can make by encouraging trade and buisiness!"
So while these repairs are going on (look in Stronghond Builder's Guilde for costs and such), the party should be doing something interesting. Hmm... Wait, didn't we say something about treasure hidden in the woods nearby? Yes, we did. That is why they came out here in the first place. Any standard dungeon crawl will do, with traps and monsters and loot at the end. I will probably throw in a suggestion once I come up with a good one. If the DM trusts that the players will be going the rout of fixing up and building upon the castle, it may be a good idea to give a little extra gold for this quest than usual. Building stronghold stuff does cost a pretty penny.
I will skip some detail for now and fill it in later as I come up with it. Still in progress. The key issue here is that the party needs more levels, more money, and last but not least needs to explore the surrounding area. This may continue till around level 10, where the adventure changes and Act II begins.

In the picture, the walls are approximately ten feet thick for reference. North is up. It is a good sized castle, larger than many that low level players might acquire. But it is going to take a lot of fixing up.

The keep itself is on a slight rise, and the shore next to the southern section is a small cliff. When the players first find the keep, there are several sections in the outer walls that have collapsed. In fact, the bandits haven't even bothered to clear rubble out of the gateway, and have been using a sizeable gap in the northmost wall as an entrance. The only section that is still mostly intact is the main structure (#4 on the map) where the bandit leader and several other members of the band have taken up residence. There are a few poorly constructed wooden huts thrown up in the courtyard, where bandits lower on the chain have been living. The bandits have not gone to great pains to clean up much, as they never planned on staying too long. One town can provide food for a bandit party for only so long before the party must move on. So the main construction challenge for the players is to fix up the structures and decorate the interior. The bandits may have collected a few things of value from the keep and pilled them all on a wagon in the courtyard. The building in the southeast corner of the courtyard is a place that the bandits have been using as a storeroom, and that is all it seems to be. But it has hidden secrets, the discovery of which will begin the next adventure.

Yes, that is a Dr. Who reference.
This is intended for when the party is around level 8.
After the party has been living in the keep for a little while, they begin hearing strange sounds at night. It is a deep rumbling coming from somewhere beneath the castle. Upon attempting to locate the source of the noise, the party follows the sounds to the basement of the building in the southeast corner of the main courtyard. This building was being used as a storehouse by the bandits, and chances are, probably something similar by the PCs. If the party looks around and listens, they can hear that the sounds seem to be coming from behind the north wall. If anyone in the party has a good engineering skill check, they might notice that a 10 foot section of this wall is a newer addition to the castle. It is covering a tunnel that was build at the same time as the rest of the castle. After a few feet of tunnel, there is a staircase that leads down into the darkness. This dungeon crawl starts in an actual dungeon, as this is exactly what the tunnel proves to be.
The entirety of this sub-quest can be found here.

The key thing in this act is city expansion. This is really where the city must take shape. Level 15 characters are supposed to be powerful and rich, so running a city is not out of the question. By the time the party gets to that level, they should have a good sized city built up. A warning for the DM: In Act II and III, the players will have control over not only their own money, but also the cities treasury. With taxes and city planning, this cash flow in and out will be much higher than their own personal incomes and fortunes. It will be important for you, the DM, to press upon them the dangers of embezzling money from the state treasury. Politicians and rulers are almost expected to indulge in a little embezzling, but you also need to have swift and harsh punishments available if they take it too far. There will be a lot of angry nobles and merchants if it is discovered that a PC emptied the state treasury to buy himself a ring of elemental command. If they ruin your game by mishandling resources and becoming too rich, you can ruin their game by having an angry mob execute them. DM lightning is also fun!

The essence of this adventure is that to turn a village into a city, there has to be some mechanism by which a lot of people are attracted to this new location. The method outlined here is why we put the keep near mountains. One adventure that they have been participating in to check out the local area leads them to a network of caves not too far from the keep. While exploring these tunnels, they come across an isolated community of underground dwellers, dwarves for example. After winning the trust of these dwellers by doing some jobs for them, getting rid of pesky stuff and the like, they find that these dwarves have access to a rich mine. They make good use of the metals they find, but they don't have good trading access to the outside world. They are willing to trade, and oh look your town is the perfect launching place for a trade rout from these mountains. Once the trade rout gets going, it can also be a good trade rout for any other resources found or grown or gathered in the area. Money money money. People come in to the town-turning-city in order to take part in the new industries. Wealth is flowing, and the power and political influence of the party is growing.

Another issue that rises with the size of the city is how it relates to other cities and nations. If the new city is in a pre-existing nation, then the party will likely have to swear allegiance to and seek the support of the rulers of the nation. If the city gets too powerful, then it may attract unwanted attention from enemies. Sieges and battles and fun galore!!